Differential pulse voltammogram

FIG. 13 Differential pulse voltammograms for Au electrode modified with el6S-tl9-T12Fc ternary complex (filled circle) and el6S-ml9-T12Fc mismatch complex (open circle). Pulse amplitude, 50 mV pulse width, 50 ms pulse period, 200 ms. Other conditions are the same as those in Fig. 12. 

Fig. 6 Plots of cyclic and differential pulse voltammograms for bpz-linked species 43 and 44 in 0.1M dichloromethane solution of (Bu4N)(PF6). The scan rates are lOOmVs-1 for CV and 20 mV s 1 for DPV...

Fig. 11 Differential pulse voltammogram of the molecularly interfaced fructose dehydrogenase (—) and simply adsorbed one...

As mentioned, DPV is particularly useful to determine accurately the formal electrode potentials of partially overlapping consecutive electron transfers. For instance, Figure 40 compares the cyclic voltammogram of a species which undergoes two closely spaced one-electron oxidations with the relative differential-pulse voltammogram. As seen in DPV the two processes are well separated. 

Figure 23 Cyclic and differential pulse voltammograms recorded at a platinum electrode in a CH2Cl2solution of [ l, 3,5- C=CRu(rj-C Hs)(PPh3)2 3 C6H3], Supporting electrolyte [NBu4][PF6] (0.2 mol dm 3). Scan rates (a) 0.2 Vs-1 (b) 0.004 V s f...

In normal pulse voltammetry, the current is sampled for a short period just before the drop is dislodged. The current monitored is assumed to be constant with time. In the differential pulse method, the current is monitored twice per drop the first sample is taken just before the rise in potential when the pulse starts, while the second is taken at the end of the current pulse just before it decreases back to the baseline. The difference between these two currents is Alpuise The differential pulse voltammogram is then a plot of current difference against potential. In... 

Figure 3.11 Differential pulse voltammograms (DPVs) for guanine at bare glassy carbon, SWNT modified glassy carbon and bamboo-modified glassy carbon. DNA cone, 0.4 mgmL (b) the corresponding DPV plots observed in (a) but with background subtraction. The signal gene rated from...

Although the hybridization of single-stranded DNA to its complement results in detectable changes in electrochemical properties, particularly in support of non-Faradaic current, the DNA bases may also demonstrate redox behavior that gives rise to Faradaic currents. The electrochemical behavior of DNA has been studied over the past few decades. Differential pulse voltammograms show clearly defined peaks for the reduction of cytosine and adenosine. Electrochemical characterization of guanine by cyclic voltammetry has shown... 

Very interesting oxidation patterns are obtained for decanuclear compounds (Scheme 1 and Table 1). For example, in compound lOC, which contains one Os " and nine Ru " ions, the Os " ion is expected to be oxidized at less positive potentials than the nine Ru ions. Furthermore, because of the different electron donor properties of the ligands, the six peripheral Ru ions are expected to be oxidized at less positive potentials than the three intermediate Ru " ions. In agreement with these expectations, the differential pulse voltammogram of IOC (Figure 12) shows... 

Fig. 20 DifFerential-pulse voltammogram of C121, (45) (a), square-wave voltammogram of C122H4, (44) (b), and Cgo (c) in o-dichlorobenzene with 0.1 M TBAP as supporting electrolyte. The first reduction potential of Cgo is shown by the dotted line. Reprinted with permission from Ref 152. Copyright 2001 American Chemical Society.

Figure 3.4 Differential pulse voltammograms with correction of background current for (a) 0.4 mM ascorbic acid, (b) 0.4 mM ascorbic acid + 0.05 mM dopamine, and (c) 0.4 mM ascorbic acid + 0.05 mM dopamine + 0.05 mM uric acid at a multiwalled carbon nanotube-ionic liquid/GC electrode. The total weight of the gel on the multiwalled carbon nanotube-ionic liquid modified electrode is 0.1 mg. Scan rate = 20 mVs. (Reprinted from Zhao, Y., Gao, Y., Zhan, D., Liu, H., Zhao, Q., Kou, Y., Shao, Y., Li, M., Zhuang, Q., and Zhu, Z., Talanta, 51-57, 2005. Copyright 2005 Elsevier. With permission.)...

This is illustrated in Fig. 2.4, where the deconvolution of differential pulse voltammograms at the glassy carbon electrode in the ethanol extract from two commercial inks are shown. Samples were taken from paper fragments of 0.10 mg immersed for 10 min in a 50 50 (v/v) ethanol 0.50 M aqueous acetate buffer (pH 4.85) solution. 

Figure 5.6 Differential pulse voltammograms of C12RuRu2 (top), C120sRu2, C12RuRu2, and C120s0s2 (bottom).

Figure 5.8 Differential pulse voltammograms of RulO (top), OsRu9 (center), and 0sRu30s6 (bottom). Fc indicate ferrocene, used as reference.

Figure 8.3 Differential pulse voltammograms of C76, C78, and C84 (tetrachloroethane + 0.1 M (w-Bu)4NPF6), using a GCE carbon electrode working and ferrocene/ferrocenium (Fc/Fc +) couple as an internal reference. Reprinted with permission from Ref. 7. Copyright 1995 American Chemical Society.

Fig. 20.5. Background-subtracted DP voltammograms of lpM adriamycin in 0.1 M pH 4.5 acetate buffer obtained with a thick-layer dsDNA-electrochemical biosensor (A) Effect of immersion time, insert /p vs. t (B) Current decrease in successive differential pulse voltammograms (—) First voltammogram after 5 min immersion and ( ) Fifth voltammogram. With permission from Ref. [37].

Fig. 29.8. Differential pulse voltammograms obtained for the samples assayed (one representative voltammogram for each of the spiked levels, from 0.5 to 15 pg/kg). Competition blank signal is relative to OTA level = 0, blank signal is OTA-free wheat extract with no OTA-AP conjugate used in the assay. Reprinted with permission from Ref. [75].

The thick-layer biosensor is immersed in a 0.1 pM of adriamydn for different times and the differential pulse voltammograms are recorded, in supporting electrolyte, after each immersion time. 

Fig. 47.2. Differential pulse voltammogram for (1) aptamer without thrombin and for aptamer at different thrombin concentrations (2) 0.28 (3) 0.57 (4) 1.14 (5) 6.8nmol/L...

Figure 6.17 Differential-pulse voltammograms for the ferrocenyl naphthalene diimide indicator at the fiTlVmodified electrode before (curve a) and after (curve b) hybridization with dA2o- Also shown is the chemical structure of the indicator. (Reproduced with permission from Ref. 72.)...

Fig. 14.22. Differential pulse voltammogram of GO and FAD on a gold electrode, a, Background current b, after 10 min adsorption of the enzyme from 5.3 iM solution c, after 40 min d, after 120 min e, electrochemical response of adsorbed FAD measured in pure buffer after 2 hr adsorption from 10 iM FAD solution and washing the electrode. (Reprinted from A. Szucs, G. D. Hitchens, and J. O M. Bockris, Bioelectrochemistry 21 133, copyright 1989. Reproduced with permission of Elsevier Science.)...

Figure 3. Differential pulse voltammogram of a mixture of dibenzothiophene and benzothiophene in acetonitrile. Supporting electrolyte 0.1 M tetraethylammonium perchlorate. Indicator electrode glassy carbon disk, rotated at 1800 rpm. Linear potential ramp, 0.002 volt/s. Pulse amplitude, AE = 0.025 V. Pulse duration, 57 ms. Current sampling time, 17 ms.

Moreover, natural nucleic acids give rise to two well-separated oxidation peaks in differential pulse voltammograms, which can be used to probe individual adenine-thymine (AT) and guanine-cytosine (GC) pairs in double helical DNA during its conformational changes [38]. Differences in signals obtained at carbon electrodes were observed according to whether, or not, the DNA was denatured [39]. 

Some similar features were observed concerning the adsorption and electrochemical oxidation of DNA on glassy carbon and tin oxide electrodes [68]. Differential pulse voltammograms were recorded in buffer solution without DNA after adsorption of DNA onto the electrode surface during a predetermined time at a fixed potential suggesting the possibility of using adsorption to preconcentrate DNA on solid electrode surfaces and use this DNA-modified electrode for analytical purposes. 

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